1
|
Alshehabi Y, Martin DDO. Protective Proteolysis in Huntington's Disease: Unraveling the Role of Post-Translational Myristoylation of Huntingtin in Autophagy. J Huntingtons Dis 2024:JHD240028. [PMID: 38995796 DOI: 10.3233/jhd-240028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
Huntington's disease (HD) is a devastating neurodegenerative disorder characterized by impaired motor function and cognitive decline, ultimately leading to death. HD is caused by a polyglutamine expansion in the N-terminal region of the huntingtin (HTT) protein, which is linked to decreased HTT turnover, increased HTT proteolysis, increased HTT aggregation, and subsequent neuronal death. In this review, we explore the mechanism of the protective effect of blocking HTT proteolysis at D586, which has been shown to rescue the HD phenotype in HD mouse models. Until recently, the mechanism remained unclear. Herein, we discuss how blocking HTT proteolysis at D586 promotes HTT turnover by correcting autophagy, and making HTT a better autophagy substrate, through post-translational myristoylation of HTT at G553.
Collapse
Affiliation(s)
- Yasmeen Alshehabi
- NeurdyPhagy Lab, Department of Biology, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Dale D O Martin
- NeurdyPhagy Lab, Department of Biology, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| |
Collapse
|
2
|
Kawanaka R, Jin H, Aoe T. Unraveling the Connection: Pain and Endoplasmic Reticulum Stress. Int J Mol Sci 2024; 25:4995. [PMID: 38732214 PMCID: PMC11084550 DOI: 10.3390/ijms25094995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024] Open
Abstract
Pain is a complex and multifaceted experience. Recent research has increasingly focused on the role of endoplasmic reticulum (ER) stress in the induction and modulation of pain. The ER is an essential organelle for cells and plays a key role in protein folding and calcium dynamics. Various pathological conditions, such as ischemia, hypoxia, toxic substances, and increased protein production, may disturb protein folding, causing an increase in misfolding proteins in the ER. Such an overload of the folding process leads to ER stress and causes the unfolded protein response (UPR), which increases folding capacity in the ER. Uncompensated ER stress impairs intracellular signaling and cell function, resulting in various diseases, such as diabetes and degenerative neurological diseases. ER stress may be a critical universal mechanism underlying human diseases. Pain sensations involve the central as well as peripheral nervous systems. Several preclinical studies indicate that ER stress in the nervous system is enhanced in various painful states, especially in neuropathic pain conditions. The purpose of this narrative review is to uncover the intricate relationship between ER stress and pain, exploring molecular pathways, implications for various pain conditions, and potential therapeutic strategies.
Collapse
Affiliation(s)
- Ryoko Kawanaka
- Department of Anesthesiology, Chiba Medical Center, Teikyo University, Ichihara 299-0111, Japan
| | - Hisayo Jin
- Department of Anesthesiology, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
| | - Tomohiko Aoe
- Pain Center, Chiba Medical Center, Teikyo University, Ichihara 299-0111, Japan
| |
Collapse
|
3
|
Tong H, Yang T, Xu S, Li X, Liu L, Zhou G, Yang S, Yin S, Li XJ, Li S. Huntington's Disease: Complex Pathogenesis and Therapeutic Strategies. Int J Mol Sci 2024; 25:3845. [PMID: 38612657 PMCID: PMC11011923 DOI: 10.3390/ijms25073845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/21/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
Huntington's disease (HD) arises from the abnormal expansion of CAG repeats in the huntingtin gene (HTT), resulting in the production of the mutant huntingtin protein (mHTT) with a polyglutamine stretch in its N-terminus. The pathogenic mechanisms underlying HD are complex and not yet fully elucidated. However, mHTT forms aggregates and accumulates abnormally in neuronal nuclei and processes, leading to disruptions in multiple cellular functions. Although there is currently no effective curative treatment for HD, significant progress has been made in developing various therapeutic strategies to treat HD. In addition to drugs targeting the neuronal toxicity of mHTT, gene therapy approaches that aim to reduce the expression of the mutant HTT gene hold great promise for effective HD therapy. This review provides an overview of current HD treatments, discusses different therapeutic strategies, and aims to facilitate future therapeutic advancements in the field.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Xiao-Jiang Li
- Guangdong Key Laboratory of Non-Human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (H.T.); (T.Y.); (S.X.); (X.L.); (L.L.); (G.Z.); (S.Y.); (S.Y.)
| | - Shihua Li
- Guangdong Key Laboratory of Non-Human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (H.T.); (T.Y.); (S.X.); (X.L.); (L.L.); (G.Z.); (S.Y.); (S.Y.)
| |
Collapse
|
4
|
Geijtenbeek KW, Aranda AS, Sanz AS, Janzen J, Bury AE, Kors S, Al Amery N, Schmitz NCM, Reits EAJ, Schipper-Krom S. Insulin-Degrading Enzyme Efficiently Degrades polyQ Peptides but not Expanded polyQ Huntingtin Fragments. J Huntingtons Dis 2024; 13:201-214. [PMID: 38640164 DOI: 10.3233/jhd-230583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
Background Huntington's disease is an inheritable autosomal dominant disorder caused by an expanded CAG trinucleotide repeat within the Huntingtin gene, leading to a polyglutamine (polyQ) expansion in the mutant protein. Objective A potential therapeutic approach for delaying or preventing the onset of the disease involves enhancing the degradation of the aggregation-prone polyQ-expanded N-terminal mutant huntingtin (mHTT) exon1 fragment. A few proteases and peptidases have been identified that are able to cleave polyQ fragments with low efficiency. This study aims to identify a potent polyQ-degrading endopeptidase. Methods Here we used quenched polyQ peptides to identify a polyQ-degrading endopeptidase. Next we investigated its role on HTT turnover, using purified polyQ-expanded HTT fragments and striatal cells expressing mHTT exon1 peptides. Results We identified insulin-degrading enzyme (IDE) as a novel endopeptidase for degrading polyQ peptides. IDE was, however, ineffective in reducing purified polyQ-expanded HTT fragments. Similarly, in striatal cells expressing mHTT exon1 peptides, IDE did not enhance mHTT turnover. Conclusions This study shows that despite IDE's efficiency in degrading polyQ peptides, it does not contribute to the direct degradation of polyQ-expanded mHTT fragments.
Collapse
Affiliation(s)
- Karlijne W Geijtenbeek
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Angela Santiago Aranda
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Alicia Sanz Sanz
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Jolien Janzen
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Aleksandra E Bury
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Suzan Kors
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | | | - Nina C M Schmitz
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Eric A J Reits
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Sabine Schipper-Krom
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| |
Collapse
|
5
|
Kuijper EC, Overzier M, Suidgeest E, Dzyubachyk O, Maguin C, Pérot JB, Flament J, Ariyurek Y, Mei H, Buijsen RAM, van der Weerd L, van Roon-Mom W. Antisense oligonucleotide-mediated disruption of HTT caspase-6 cleavage site ameliorates the phenotype of YAC128 Huntington disease mice. Neurobiol Dis 2024; 190:106368. [PMID: 38040383 DOI: 10.1016/j.nbd.2023.106368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/20/2023] [Accepted: 11/28/2023] [Indexed: 12/03/2023] Open
Abstract
In Huntington disease, cellular toxicity is particularly caused by toxic protein fragments generated from the mutant huntingtin (HTT) protein. By modifying the HTT protein, we aim to reduce proteolytic cleavage and ameliorate the consequences of mutant HTT without lowering total HTT levels. To that end, we use an antisense oligonucleotide (AON) that targets HTT pre-mRNA and induces partial skipping of exon 12, which contains the critical caspase-6 cleavage site. Here, we show that AON-treatment can partially restore the phenotype of YAC128 mice, a mouse model expressing the full-length human HTT gene including 128 CAG-repeats. Wild-type and YAC128 mice were treated intracerebroventricularly with AON12.1, scrambled AON or vehicle starting at 6 months of age and followed up to 12 months of age, when MRI was performed and mice were sacrificed. AON12.1 treatment induced around 40% exon skip and protein modification. The phenotype on body weight and activity, but not rotarod, was restored by AON treatment. Genes differentially expressed in YAC128 striatum changed toward wild-type levels and striatal volume was preserved upon AON12.1 treatment. However, scrambled AON also showed a restorative effect on gene expression and appeared to generally increase brain volume.
Collapse
Affiliation(s)
- Elsa C Kuijper
- Department of Human Genetics, Leiden University Medical Center, the Netherlands.
| | - Maurice Overzier
- Department of Human Genetics, Leiden University Medical Center, the Netherlands
| | - Ernst Suidgeest
- Department of Radiology, Leiden University Medical Center, the Netherlands
| | - Oleh Dzyubachyk
- Department of Radiology, Leiden University Medical Center, the Netherlands
| | - Cécile Maguin
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, Molecular Imaging Research Center, Laboratoire des Maladies Neurodégénératives, France
| | - Jean-Baptiste Pérot
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, Molecular Imaging Research Center, Laboratoire des Maladies Neurodégénératives, France; Institut du Cerveau - Paris Brain Institute, Sorbonne Université, France
| | - Julien Flament
- Université Paris-Saclay, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, Molecular Imaging Research Center, Laboratoire des Maladies Neurodégénératives, France
| | - Yavuz Ariyurek
- Department of Human Genetics, Leiden University Medical Center, the Netherlands
| | - Hailiang Mei
- Department of Biomedical Data Sciences, Leiden University Medical Center, the Netherlands
| | - Ronald A M Buijsen
- Department of Human Genetics, Leiden University Medical Center, the Netherlands
| | - Louise van der Weerd
- Department of Human Genetics, Leiden University Medical Center, the Netherlands; Department of Radiology, Leiden University Medical Center, the Netherlands
| | | |
Collapse
|
6
|
Zhou S, Zhou Y, Zhong W, Su Z, Qin Z. Involvement of protein L-isoaspartyl methyltransferase in the physiopathology of neurodegenerative diseases: Possible substrates associated with synaptic function. Neurochem Int 2023; 170:105606. [PMID: 37657764 DOI: 10.1016/j.neuint.2023.105606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/03/2023]
Abstract
Synaptic dysfunction is a typical pathophysiologic change in neurodegenerative diseases (NDs) such as Alzheimer's disease (AD), Parkinson's disease (PD), Hintington's disease (HD) and amyotrophic lateral sclerosis (ALS), which involves protein post-translational modifications (PTMs) including L-isoaspartate (L-isoAsp) formed by isomerization of aspartate or deamidation of asparagine. The formation of L-isoAsp could be repaired by protein L-isoaspartyl methyltransferase (PIMT). Some synaptic proteins have been identified as PIMT potential substrates and play an essential role in ensuring synaptic function. In this review, we discuss the role of certain synaptic proteins as PIMT substrates in neurodegenerative disease, thus providing therapeutic synapse-centered targets for the treatment of NDs.
Collapse
Affiliation(s)
- Sirui Zhou
- Department of Anatomy, School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Yancheng Zhou
- Department of Anatomy, School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Wanyu Zhong
- Department of Anatomy, School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Zhonghao Su
- Department of Febrile Disease, School of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Zhenxia Qin
- Department of Anatomy, School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| |
Collapse
|
7
|
Almeida LM, Oliveira Â, Oliveira JMA, Pinho BR. Stress response mechanisms in protein misfolding diseases: Profiling a cellular model of Huntington's disease. Arch Biochem Biophys 2023; 745:109711. [PMID: 37541563 DOI: 10.1016/j.abb.2023.109711] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/14/2023] [Accepted: 08/01/2023] [Indexed: 08/06/2023]
Abstract
Stress response pathways like the integrated stress response (ISR), the mitochondrial unfolded protein response (UPRmt) and the heat shock response (HSR) have emerged as part of the pathophysiology of neurodegenerative diseases, including Huntington's disease (HD) - a currently incurable disease caused by the production of mutant huntingtin (mut-Htt). Previous data from HD patients suggest that ISR is activated while UPRmt and HSR are impaired in HD. The study of these stress response pathways as potential therapeutic targets in HD requires cellular models that mimic the activation status found in HD patients of such pathways. PC12 cells with inducible expression of the N-terminal fragment of mut-Htt are among the most used cell lines to model HD, however the activation of stress responses remains unclear in this model. The goal of this study is to characterize the activation of ISR, UPRmt and HSR in this HD cell model and evaluate if it mimics the activation status found in HD patients. We show that PC12 HD cell model presents reduced levels of Hsp90 and mitochondrial chaperones, suggesting an impaired activation or function of HSR and UPRmt. This HD model also presents increased levels of phosphorylated eIF2α, the master regulator of the ISR, but overall similar levels of ATF4 and decreased levels of CHOP - transcription factors downstream to eIF2α - in comparison to control, suggesting an initial activation of ISR. These results show that this model mimics the ISR activation and the impaired UPRmt and HSR found in HD patients. This work suggests that the PC12 N-terminal HD model is suitable for studying the role of stress response pathways in the pathophysiology of HD and for exploratory studies investigating the therapeutic potential of drugs targeting stress responses.
Collapse
Affiliation(s)
- Liliana M Almeida
- UCIBIO-REQUIMTE - Applied Molecular Biosciences Unit, Mitochondria and Neurobiology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, Department of Drug Sciences, Pharmacology Lab, University of Porto, 4050-313 Porto, Portugal
| | - Ângela Oliveira
- UCIBIO-REQUIMTE - Applied Molecular Biosciences Unit, Mitochondria and Neurobiology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, Department of Drug Sciences, Pharmacology Lab, University of Porto, 4050-313 Porto, Portugal
| | - Jorge M A Oliveira
- UCIBIO-REQUIMTE - Applied Molecular Biosciences Unit, Mitochondria and Neurobiology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, Department of Drug Sciences, Pharmacology Lab, University of Porto, 4050-313 Porto, Portugal.
| | - Brígida R Pinho
- UCIBIO-REQUIMTE - Applied Molecular Biosciences Unit, Mitochondria and Neurobiology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, Department of Drug Sciences, Pharmacology Lab, University of Porto, 4050-313 Porto, Portugal.
| |
Collapse
|
8
|
Lemarié FL, Sanders SS, Nguyen Y, Martin DDO, Hayden MR. Full-length huntingtin is palmitoylated at multiple sites and post-translationally myristoylated following caspase-cleavage. Front Physiol 2023; 14:1086112. [PMID: 36711022 PMCID: PMC9880554 DOI: 10.3389/fphys.2023.1086112] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/02/2023] [Indexed: 01/15/2023] Open
Abstract
Introduction: Huntington disease is an autosomal dominant neurodegenerative disorder which is caused by a CAG repeat expansion in the HTT gene that codes for an elongated polyglutamine tract in the huntingtin (HTT) protein. Huntingtin is subjected to multiple post-translational modifications which regulate its cellular functions and degradation. We have previously identified a palmitoylation site at cysteine 214 (C214), catalyzed by the enzymes ZDHHC17 and ZDHHC13. Reduced palmitoylation level of mutant huntingtin is linked to toxicity and loss of function. Moreover, we have described N-terminal myristoylation by the N-myristoyltransferases of a short fragment of huntingtin (HTT553-586) at glycine 553 (G553) following proteolysis at aspartate 552 (D552). Results: Here, we show that huntingtin is palmitoylated at numerous cysteines: C105, C433, C3134 and C3144. In addition, we confirm that full-length huntingtin is cleaved at D552 and post-translationally myristoylated at G553. Importantly, blocking caspase cleavage at the critical and pathogenic aspartate 586 (D586) significantly increases posttranslational myristoylation of huntingtin. In turn, myristoylation of huntingtin promotes the co-interaction between C-terminal and N-terminal huntingtin fragments, which is also protective. Discussion: This suggests that the protective effect of inhibiting caspase-cleavage at D586 may be mediated through post-translational myristoylation of huntingtin at G553.
Collapse
|
9
|
Huntingtin and Other Neurodegeneration-Associated Proteins in the Development of Intracellular Pathologies: Potential Target Search for Therapeutic Intervention. Int J Mol Sci 2022; 23:ijms232415533. [PMID: 36555175 PMCID: PMC9779313 DOI: 10.3390/ijms232415533] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases are currently incurable. Numerous experimental data accumulated over the past fifty years have brought us closer to understanding the molecular and cell mechanisms responsible for their development. However, these data are not enough for a complete understanding of the genesis of these diseases, nor to suggest treatment methods. It turns out that many cellular pathologies developing during neurodegeneration coincide from disease to disease. These observations give hope to finding a common intracellular target(s) and to offering a universal method of treatment. In this review, we attempt to analyze data on similar cellular disorders among neurodegenerative diseases in general, and polyglutamine neurodegenerative diseases in particular, focusing on the interaction of various proteins involved in the development of neurodegenerative diseases with various cellular organelles. The main purposes of this review are: (1) to outline the spectrum of common intracellular pathologies and to answer the question of whether it is possible to find potential universal target(s) for therapeutic intervention; (2) to identify specific intracellular pathologies and to speculate about a possible general approach for their treatment.
Collapse
|
10
|
Incebacak Eltemur RD, Nguyen HP, Weber JJ. Calpain-mediated proteolysis as driver and modulator of polyglutamine toxicity. Front Mol Neurosci 2022; 15:1020104. [PMID: 36385755 PMCID: PMC9648470 DOI: 10.3389/fnmol.2022.1020104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 09/26/2022] [Indexed: 09/22/2023] Open
Abstract
Among posttranslational modifications, directed proteolytic processes have the strongest impact on protein integrity. They are executed by a variety of cellular machineries and lead to a wide range of molecular consequences. Compared to other forms of proteolytic enzymes, the class of calcium-activated calpains is considered as modulator proteases due to their limited proteolytic activity, which changes the structure and function of their target substrates. In the context of neurodegeneration and - in particular - polyglutamine disorders, proteolytic events have been linked to modulatory effects on the molecular pathogenesis by generating harmful breakdown products of disease proteins. These findings led to the formulation of the toxic fragment hypothesis, and calpains appeared to be one of the key players and auspicious therapeutic targets in Huntington disease and Machado Joseph disease. This review provides a current survey of the role of calpains in proteolytic processes found in polyglutamine disorders. Together with insights into general concepts behind toxic fragments and findings in polyglutamine disorders, this work aims to inspire researchers to broaden and deepen the knowledge in this field, which will help to evaluate calpain-mediated proteolysis as a unifying and therapeutically targetable posttranslational mechanism in neurodegeneration.
Collapse
Affiliation(s)
- Rana Dilara Incebacak Eltemur
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Huu Phuc Nguyen
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Jonasz Jeremiasz Weber
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| |
Collapse
|
11
|
van der Bent ML, Evers MM, Vallès A. Emerging Therapies for Huntington's Disease - Focus on N-Terminal Huntingtin and Huntingtin Exon 1. Biologics 2022; 16:141-160. [PMID: 36213816 PMCID: PMC9532260 DOI: 10.2147/btt.s270657] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/14/2022] [Indexed: 11/12/2022]
Abstract
Huntington's disease is a devastating heritable neurodegenerative disorder that is caused by the presence of a trinucleotide CAG repeat expansion in the Huntingtin gene, leading to a polyglutamine tract in the protein. Various mechanisms lead to the production of N-terminal Huntingtin protein fragments, which are reportedly more toxic than the full-length protein. In this review, we summarize the current knowledge on the production and toxicity of N-terminal Huntingtin protein fragments. Further, we expand on various therapeutic strategies targeting N-terminal Huntingtin on the protein, RNA and DNA level. Finally, we compare the therapeutic approaches that are clinically most advanced, including those that do not target N-terminal Huntingtin, discussing differences in mode of action and translational applicability.
Collapse
Affiliation(s)
| | - Melvin M Evers
- uniQure biopharma B.V., Department of Research and Development, Amsterdam, the Netherlands
| | - Astrid Vallès
- uniQure biopharma B.V., Department of Research and Development, Amsterdam, the Netherlands
| |
Collapse
|
12
|
Donnelly KM, Coleman CM, Fuller ML, Reed VL, Smerina D, Tomlinson DS, Pearce MMP. Hunting for the cause: Evidence for prion-like mechanisms in Huntington’s disease. Front Neurosci 2022; 16:946822. [PMID: 36090278 PMCID: PMC9448931 DOI: 10.3389/fnins.2022.946822] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/28/2022] [Indexed: 11/23/2022] Open
Abstract
The hypothesis that pathogenic protein aggregates associated with neurodegenerative diseases spread from cell-to-cell in the brain in a manner akin to infectious prions has gained substantial momentum due to an explosion of research in the past 10–15 years. Here, we review current evidence supporting the existence of prion-like mechanisms in Huntington’s disease (HD), an autosomal dominant neurodegenerative disease caused by expansion of a CAG repeat tract in exon 1 of the huntingtin (HTT) gene. We summarize information gained from human studies and in vivo and in vitro models of HD that strongly support prion-like features of the mutant HTT (mHTT) protein, including potential involvement of molecular features of mHTT seeds, synaptic structures and connectivity, endocytic and exocytic mechanisms, tunneling nanotubes, and nonneuronal cells in mHTT propagation in the brain. We discuss mechanisms by which mHTT aggregate spreading and neurotoxicity could be causally linked and the potential benefits of targeting prion-like mechanisms in the search for new disease-modifying therapies for HD and other fatal neurodegenerative diseases.
Collapse
Affiliation(s)
- Kirby M. Donnelly
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Cevannah M. Coleman
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Madison L. Fuller
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Victoria L. Reed
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Dayna Smerina
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - David S. Tomlinson
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
| | - Margaret M. Panning Pearce
- Department of Biological Sciences, University of the Sciences, Philadelphia, PA, United States
- Department of Biology, Saint Joseph’s University, Philadelphia, PA, United States
- *Correspondence: Margaret M. Panning Pearce,
| |
Collapse
|
13
|
Fourest-Lieuvin A, Vinit A, Blot B, Perrot A, Denarier E, Saudou F, Arnal I. Controlled Tau Cleavage in Cells Reveals Abnormal Localizations of Tau Fragments. Neuroscience 2022; 518:162-177. [PMID: 35995336 DOI: 10.1016/j.neuroscience.2022.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 06/08/2022] [Accepted: 08/16/2022] [Indexed: 11/15/2022]
Abstract
In several forms of dementia, such as Alzheimer's disease, the cytoskeleton-associated protein tau undergoes proteolysis, giving rise to fragments that have a toxic impact on neuronal homeostasis. How these fragments interact with cellular structures, in particular with the cytoskeleton, is currently incompletely understood. Here, we developed a method, derived from a Tobacco Etch Virus (TEV) protease system, to induce controlled cleavage of tau at specific sites. Five tau proteins containing specific TEV recognition sites corresponding to pathological proteolytic sites were engineered, and tagged with GFP at one end and mCherry at the other. Following controlled cleavage to produce GFP-N-terminal and C-terminal-mCherry fragments, we followed the fate of tau fragments in cells. Our results showed that whole engineered tau proteins associate with the cytoskeleton similarly to the non-modified tau, whereas tau fragments adopted different localizations with respect to the actin and microtubule cytoskeletons. These distinct localizations were confirmed by expressing each separate fragment in cells. Some cleavages - in particular cleavages at amino-acid positions 124 or 256 - displayed a certain level of cellular toxicity, with an unusual relocalization of the N-terminal fragments to the nucleus. Based on the data presented here, inducible cleavage of tau by the TEV protease appears to be a valuable tool to reproduce tau fragmentation in cells and study the resulting consequences on cell physiology.
Collapse
Affiliation(s)
- Anne Fourest-Lieuvin
- Université Grenoble Alpes, INSERM, U1216, CEA, CNRS, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France.
| | - Angélique Vinit
- Université Grenoble Alpes, INSERM, U1216, CEA, CNRS, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Béatrice Blot
- Université Grenoble Alpes, INSERM, U1216, CEA, CNRS, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Anthime Perrot
- Université Grenoble Alpes, INSERM, U1216, CEA, CNRS, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Eric Denarier
- Université Grenoble Alpes, INSERM, U1216, CEA, CNRS, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Frédéric Saudou
- Université Grenoble Alpes, INSERM, U1216, CEA, CNRS, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Isabelle Arnal
- Université Grenoble Alpes, INSERM, U1216, CEA, CNRS, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France.
| |
Collapse
|
14
|
Kim H, Lenoir S, Helfricht A, Jung T, Karneva ZK, Lee Y, Beumer W, van der Horst GB, Anthonijsz H, Buil LC, van der Ham F, Platenburg GJ, Purhonen P, Hebert H, Humbert S, Saudou F, Klein P, Song JJ. A pathogenic proteolysis-resistant huntingtin isoform induced by an antisense oligonucleotide maintains huntingtin function. JCI Insight 2022; 7:154108. [PMID: 35943803 PMCID: PMC9536263 DOI: 10.1172/jci.insight.154108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 08/03/2022] [Indexed: 11/17/2022] Open
Abstract
Huntington’s disease (HD) is a late-onset neurological disorder for which therapeutics are not available. Its key pathological mechanism involves the proteolysis of polyglutamine-expanded (polyQ-expanded) mutant huntingtin (mHTT), which generates N-terminal fragments containing polyQ, a key contributor to HD pathogenesis. Interestingly, a naturally occurring spliced form of HTT mRNA with truncated exon 12 encodes an HTT (HTTΔ12) with a deletion near the caspase-6 cleavage site. In this study, we used a multidisciplinary approach to characterize the therapeutic potential of targeting HTT exon 12. We show that HTTΔ12 was resistant to caspase-6 cleavage in both cell-free and tissue lysate assays. However, HTTΔ12 retained overall biochemical and structural properties similar to those of wt-HTT. We generated mice in which HTT exon 12 was truncated and found that the canonical exon 12 was dispensable for the main physiological functions of HTT, including embryonic development and intracellular trafficking. Finally, we pharmacologically induced HTTΔ12 using the antisense oligonucleotide (ASO) QRX-704. QRX-704 showed predictable pharmacology and efficient biodistribution. In addition, it was stable for several months and inhibited pathogenic proteolysis. Furthermore, QRX-704 treatments resulted in a reduction of HTT aggregation and an increase in dendritic spine count. Thus, ASO-induced HTT exon 12 splice switching from HTT may provide an alternative therapeutic strategy for HD.
Collapse
Affiliation(s)
- Hyeongju Kim
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
| | - Sophie Lenoir
- Grenoble Institute Neurosciences, University Grenoble Alpes, Grenoble, France
| | | | - Taeyang Jung
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
| | | | - Yejin Lee
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
| | | | | | | | | | | | | | - Pasi Purhonen
- Department of Biomedical Engineering and Health Systems, The Royal Institute of Technology, KTH, Huddinge, Sweden
| | - Hans Hebert
- Department of Biomedical Engineering and Health Systems, The Royal Institute of Technology, KTH, Huddinge, Sweden
| | - Sandrine Humbert
- Grenoble Institute Neurosciences, University Grenoble Alpes, Grenoble, France
| | - Frédéric Saudou
- Grenoble Institute Neurosciences, University Grenoble Alpes, Grenoble, France
| | | | - Ji-Joon Song
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
| |
Collapse
|
15
|
Seefelder M, Klein FAC, Landwehrmeyer B, Fernández-Busnadiego R, Kochanek S. Huntingtin and Its Partner Huntingtin-Associated Protein 40: Structural and Functional Considerations in Health and Disease. J Huntingtons Dis 2022; 11:227-242. [PMID: 35871360 PMCID: PMC9484127 DOI: 10.3233/jhd-220543] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the discovery of the mutation causing Huntington’s disease (HD) in 1993, it has been debated whether an expanded polyglutamine (polyQ) stretch affects the properties of the huntingtin (HTT) protein and thus contributes to the pathological mechanisms responsible for HD. Here we review the current knowledge about the structure of HTT, alone (apo-HTT) or in a complex with Huntingtin-Associated Protein 40 (HAP40), the influence of polyQ-length variation on apo-HTT and the HTT-HAP40 complex, and the biology of HAP40. Phylogenetic analyses suggest that HAP40 performs essential functions. Highlighting the relevance of its interaction with HTT, HAP40 is one of the most abundant partners copurifying with HTT and is rapidly degraded, when HTT levels are reduced. As the levels of both proteins decrease during disease progression, HAP40 could also be a biomarker for HD. Whether declining HAP40 levels contribute to disease etiology is an open question. Structural studies have shown that the conformation of apo-HTT is less constrained but resembles that adopted in the HTT-HAP40 complex, which is exceptionally stable because of extensive interactions between HAP40 and the three domains of HTT. The complex— and to some extent apo-HTT— resists fragmentation after limited proteolysis. Unresolved regions of apo-HTT, constituting about 25% of the protein, are the main sites of post-translational modifications and likely have major regulatory functions. PolyQ elongation does not substantially alter the structure of HTT, alone or when associated with HAP40. Particularly, polyQ above the disease length threshold does not induce drastic conformational changes in full-length HTT. Therefore, models of HD pathogenesis stating that polyQ expansion drastically alters HTT properties should be reconsidered.
Collapse
Affiliation(s)
| | | | | | - Rubén Fernández-Busnadiego
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | | |
Collapse
|
16
|
Martí-Martínez S, Valor LM. A Glimpse of Molecular Biomarkers in Huntington's Disease. Int J Mol Sci 2022; 23:ijms23105411. [PMID: 35628221 PMCID: PMC9142992 DOI: 10.3390/ijms23105411] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 12/15/2022] Open
Abstract
Huntington's disease (HD) is a devastating neurodegenerative disorder that is caused by an abnormal expansion of CAG repeats in the Huntingtin (HTT) gene. Although the main symptomatology is explained by alterations at the level of the central nervous system, predominantly affecting the basal ganglia, a peripheral component of the disease is being increasingly acknowledged. Therefore, the manifestation of the disease is complex and variable among CAG expansion carriers, introducing uncertainty in the appearance of specific signs, age of onset and severity of disease. The monogenic nature of the disorder allows a precise diagnosis, but the use of biomarkers with prognostic value is still needed to achieve clinical management of the patients in an individual manner. In addition, we need tools to evaluate the patient's response to potential therapeutic approaches. In this review, we provide a succinct summary of the most interesting molecular biomarkers that have been assessed in patients, mostly obtained from body fluids such as cerebrospinal fluid, peripheral blood and saliva.
Collapse
Affiliation(s)
- Silvia Martí-Martínez
- Servicio de Neurología, Hospital General Universitario Dr. Balmis, Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), 03010 Alicante, Spain;
| | - Luis M. Valor
- Laboratorio de Apoyo a la Investigación, Hospital General Universitario Dr. Balmis, Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), 03010 Alicante, Spain
- Correspondence: ; Tel.: +34-965-913-988
| |
Collapse
|
17
|
Moretto E, Stuart S, Surana S, Vargas JNS, Schiavo G. The Role of Extracellular Matrix Components in the Spreading of Pathological Protein Aggregates. Front Cell Neurosci 2022; 16:844211. [PMID: 35573838 PMCID: PMC9100790 DOI: 10.3389/fncel.2022.844211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 03/08/2022] [Indexed: 11/23/2022] Open
Abstract
Several neurodegenerative diseases are characterized by the accumulation of aggregated misfolded proteins. These pathological agents have been suggested to propagate in the brain via mechanisms similar to that observed for the prion protein, where a misfolded variant is transferred from an affected brain region to a healthy one, thereby inducing the misfolding and/or aggregation of correctly folded copies. This process has been characterized for several proteins, such as α-synuclein, tau, amyloid beta (Aβ) and less extensively for huntingtin and TDP-43. α-synuclein, tau, TDP-43 and huntingtin are intracellular proteins, and their aggregates are located in the cytosol or nucleus of neurons. They have been shown to spread between cells and this event occurs, at least partially, via secretion of these protein aggregates in the extracellular space followed by re-uptake. Conversely, Aβ aggregates are found mainly extracellularly, and their spreading occurs in the extracellular space between brain regions. Due to the inherent nature of their spreading modalities, these proteins are exposed to components of the extracellular matrix (ECM), including glycans, proteases and core matrix proteins. These ECM components can interact with or process pathological misfolded proteins, potentially changing their properties and thus regulating their spreading capabilities. Here, we present an overview of the documented roles of ECM components in the spreading of pathological protein aggregates in neurodegenerative diseases with the objective of identifying the current gaps in knowledge and stimulating further research in the field. This could potentially lead to the identification of druggable targets to slow down the spreading and/or progression of these pathologies.
Collapse
Affiliation(s)
- Edoardo Moretto
- Institute of Neuroscience, National Research Council, CNR, Milan, Italy
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- *Correspondence: Edoardo Moretto,
| | - Skye Stuart
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Sunaina Surana
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- UCL Queen Square Motor Neuron Disease Centre, University College London, London, United Kingdom
| | - Jose Norberto S. Vargas
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- UCL Queen Square Motor Neuron Disease Centre, University College London, London, United Kingdom
| | - Giampietro Schiavo
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- UCL Queen Square Motor Neuron Disease Centre, University College London, London, United Kingdom
- Giampietro Schiavo,
| |
Collapse
|
18
|
Weber JJ, Anger SC, Pereira Sena P, Incebacak Eltemur RD, Huridou C, Fath F, Gross C, Casadei N, Riess O, Nguyen HP. Calpains as novel players in the molecular pathogenesis of spinocerebellar ataxia type 17. Cell Mol Life Sci 2022; 79:262. [PMID: 35482253 PMCID: PMC9050766 DOI: 10.1007/s00018-022-04274-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 03/07/2022] [Accepted: 03/25/2022] [Indexed: 11/23/2022]
Abstract
Spinocerebellar ataxia type 17 (SCA17) is a neurodegenerative disease caused by a polyglutamine-encoding trinucleotide repeat expansion in the gene of transcription factor TATA box-binding protein (TBP). While its underlying pathomechanism is elusive, polyglutamine-expanded TBP fragments of unknown origin mediate the mutant protein’s toxicity. Calcium-dependent calpain proteases are protagonists in neurodegenerative disorders. Here, we demonstrate that calpains cleave TBP, and emerging C-terminal fragments mislocalize to the cytoplasm. SCA17 cell and rat models exhibited calpain overactivation, leading to excessive fragmentation and depletion of neuronal proteins in vivo. Transcriptome analysis of SCA17 cells revealed synaptogenesis and calcium signaling perturbations, indicating the potential cause of elevated calpain activity. Pharmacological or genetic calpain inhibition reduced TBP cleavage and aggregation, consequently improving cell viability. Our work underlines the general significance of calpains and their activating pathways in neurodegenerative disorders and presents these proteases as novel players in the molecular pathogenesis of SCA17.
Collapse
Affiliation(s)
- Jonasz Jeremiasz Weber
- Department of Human Genetics, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany
| | - Stefanie Cari Anger
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany
| | - Priscila Pereira Sena
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany.,Graduate School of Cellular Neuroscience, University of Tübingen, 72074, Tübingen, Germany
| | - Rana Dilara Incebacak Eltemur
- Department of Human Genetics, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany
| | - Chrisovalantou Huridou
- Department of Human Genetics, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany
| | - Florian Fath
- Department of Human Genetics, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany
| | - Caspar Gross
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany.,NGS Competence Center Tübingen, 72076, Tübingen, Germany
| | - Nicolas Casadei
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany.,NGS Competence Center Tübingen, 72076, Tübingen, Germany
| | - Olaf Riess
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany.,NGS Competence Center Tübingen, 72076, Tübingen, Germany
| | - Huu Phuc Nguyen
- Department of Human Genetics, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.
| |
Collapse
|
19
|
Nuclear and cytoplasmic huntingtin inclusions exhibit distinct biochemical composition, interactome and ultrastructural properties. Nat Commun 2021; 12:6579. [PMID: 34772920 PMCID: PMC8589980 DOI: 10.1038/s41467-021-26684-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
Despite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington's disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt cytoplasmic and nuclear inclusions in mammalian cells and primary neurons overexpressing mutant exon1 of the Htt protein. Our findings provide unique insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve the polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; the recruitment and accumulation of remodeled or dysfunctional membranous organelles, and the impairment of the protein quality control and degradation machinery. We also show that nuclear and cytoplasmic Htt inclusions exhibit distinct biochemical compositions and ultrastructural properties, suggesting different mechanisms of aggregation and toxicity.
Collapse
|
20
|
Huntingtin and Its Role in Mechanisms of RNA-Mediated Toxicity. Toxins (Basel) 2021; 13:toxins13070487. [PMID: 34357961 PMCID: PMC8310054 DOI: 10.3390/toxins13070487] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 12/20/2022] Open
Abstract
Huntington’s disease (HD) is caused by a CAG-repeat expansion mutation in the Huntingtin (HTT) gene. It is characterized by progressive psychiatric and neurological symptoms in combination with a progressive movement disorder. Despite the ubiquitous expression of HTT, pathological changes occur quite selectively in the central nervous system. Since the discovery of HD more than 150 years ago, a lot of research on molecular mechanisms contributing to neurotoxicity has remained the focal point. While traditionally, the protein encoded by the HTT gene remained the cynosure for researchers and was extensively reviewed elsewhere, several studies in the last few years clearly indicated the contribution of the mutant RNA transcript to cellular dysfunction as well. In this review, we outline recent studies on RNA-mediated molecular mechanisms that are linked to cellular dysfunction in HD models. These mechanisms include mis-splicing, aberrant translation, deregulation of the miRNA machinery, deregulated RNA transport and abnormal regulation of mitochondrial RNA. Furthermore, we summarize recent therapeutical approaches targeting the mutant HTT transcript. While currently available treatments are of a palliative nature only and do not halt the disease progression, recent clinical studies provide hope that these novel RNA-targeting strategies will lead to better therapeutic approaches.
Collapse
|
21
|
Barron JC, Hurley EP, Parsons MP. Huntingtin and the Synapse. Front Cell Neurosci 2021; 15:689332. [PMID: 34211373 PMCID: PMC8239291 DOI: 10.3389/fncel.2021.689332] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/24/2021] [Indexed: 12/16/2022] Open
Abstract
Huntington disease (HD) is a monogenic disease that results in a combination of motor, psychiatric and cognitive symptoms. HD is caused by a CAG trinucleotide repeat expansion in the huntingtin (HTT) gene, which results in the production of a pathogenic mutant HTT protein (mHTT). Although there is no cure at present for HD, a number of RNA-targeting therapies have recently entered clinical trials which aim to lower mHTT production through the use of antisense oligonucleotides (ASOs) and RNAi. However, many of these treatment strategies are non-selective in that they cannot differentiate between non-pathogenic wild type HTT (wtHTT) and the mHTT variant. As HD patients are already born with decreased levels of wtHTT, these genetic therapies may result in critically low levels of wtHTT. The consequence of wtHTT reduction in the adult brain is currently under debate, and here we argue that wtHTT loss is not well-tolerated at the synaptic level. Synaptic dysfunction is an extremely sensitive measure of subsequent cell death, and is known to precede neurodegeneration in numerous brain diseases including HD. The present review focuses on the prominent role of wtHTT at the synapse and considers the consequences of wtHTT loss on both pre- and postsynaptic function. We discuss how wtHTT is implicated in virtually all major facets of synaptic neurotransmission including anterograde and retrograde transport of proteins to/from terminal buttons and dendrites, neurotransmitter release, endocytic vesicle recycling, and postsynaptic receptor localization and recycling. We conclude that wtHTT presence is essential for proper synaptic function.
Collapse
Affiliation(s)
- Jessica C Barron
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Emily P Hurley
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Matthew P Parsons
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| |
Collapse
|
22
|
Chongtham A, Bornemann DJ, Barbaro BA, Lukacsovich T, Agrawal N, Syed A, Worthge S, Purcell J, Burke J, Chin TM, Marsh JL. Effects of flanking sequences and cellular context on subcellular behavior and pathology of mutant HTT. Hum Mol Genet 2021; 29:674-688. [PMID: 31943010 DOI: 10.1093/hmg/ddaa001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/06/2019] [Accepted: 01/07/2020] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD) is caused by an expansion of a poly glutamine (polyQ) stretch in the huntingtin protein (HTT) that is necessary to cause pathology and formation of HTT aggregates. Here we ask whether expanded polyQ is sufficient to cause pathology and aggregate formation. By addressing the sufficiency question, one can identify cellular processes and structural parameters that influence HD pathology and HTT subcellular behavior (i.e. aggregation state and subcellular location). Using Drosophila, we compare the effects of expressing mutant full-length human HTT (fl-mHTT) to the effects of mutant human HTTexon1 and to two commonly used synthetic fragments, HTT171 and shortstop (HTT118). Expanded polyQ alone is not sufficient to cause inclusion formation since full-length HTT and HTTex1 with expanded polyQ are both toxic although full-length HTT remains diffuse while HTTex1 forms inclusions. Further, inclusions are not sufficient to cause pathology since HTT171-120Q forms inclusions but is benign and co-expression of HTT171-120Q with non-aggregating pathogenic fl-mHTT recruits fl-mHTT to aggregates and rescues its pathogenicity. Additionally, the influence of sequences outside the expanded polyQ domain is revealed by finding that small modifications to the HTT118 or HTT171 fragments can dramatically alter their subcellular behavior and pathogenicity. Finally, mutant HTT subcellular behavior is strongly modified by different cell and tissue environments (e.g. fl-mHTT appears as diffuse nuclear in one tissue and diffuse cytoplasmic in another but toxic in both). These observations underscore the importance of cellular and structural context for the interpretation and comparison of experiments using different fragments and tissues to report the effects of expanded polyQ.
Collapse
Affiliation(s)
- Anjalika Chongtham
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA.,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125
| | - Douglas J Bornemann
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - Brett A Barbaro
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - Tamas Lukacsovich
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - Namita Agrawal
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - Adeela Syed
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - Shane Worthge
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - Judith Purcell
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - John Burke
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| | - Theodore M Chin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125
| | - J Lawrence Marsh
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697-2300, USA
| |
Collapse
|
23
|
Ananbeh H, Vodicka P, Kupcova Skalnikova H. Emerging Roles of Exosomes in Huntington's Disease. Int J Mol Sci 2021; 22:ijms22084085. [PMID: 33920936 PMCID: PMC8071291 DOI: 10.3390/ijms22084085] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 02/07/2023] Open
Abstract
Huntington’s disease (HD) is a rare hereditary autosomal dominant neurodegenerative disorder, which is caused by expression of mutant huntingtin protein (mHTT) with an abnormal number of glutamine repeats in its N terminus, and characterized by intracellular mHTT aggregates (inclusions) in the brain. Exosomes are small extracellular vesicles that are secreted generally by all cell types and can be isolated from almost all body fluids such as blood, urine, saliva, and cerebrospinal fluid. Exosomes may participate in the spreading of toxic misfolded proteins across the central nervous system in neurodegenerative diseases. In HD, such propagation of mHTT was observed both in vitro and in vivo. On the other hand, exosomes might carry molecules with neuroprotective effects. In addition, due to their capability to cross blood-brain barrier, exosomes hold great potential as sources of biomarkers available from periphery or carriers of therapeutics into the central nervous system. In this review, we discuss the emerging roles of exosomes in HD pathogenesis, diagnosis, and therapy.
Collapse
|
24
|
Iuliano M, Seeley C, Sapp E, Jones EL, Martin C, Li X, DiFiglia M, Kegel-Gleason KB. Disposition of Proteins and Lipids in Synaptic Membrane Compartments Is Altered in Q175/Q7 Huntington's Disease Mouse Striatum. Front Synaptic Neurosci 2021; 13:618391. [PMID: 33815086 PMCID: PMC8013775 DOI: 10.3389/fnsyn.2021.618391] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Dysfunction at synapses is thought to be an early change contributing to cognitive, psychiatric and motor disturbances in Huntington's disease (HD). In neurons, mutant Huntingtin collects in aggregates and distributes to the same sites as wild-type Huntingtin including on membranes and in synapses. In this study, we investigated the biochemical integrity of synapses in HD mouse striatum. We performed subcellular fractionation of striatal tissue from 2 and 6-month old knock-in Q175/Q7 HD and Q7/Q7 mice. Compared to striata of Q7/Q7 mice, proteins including GLUT3, Na+/K+ ATPase, NMDAR 2b, PSD95, and VGLUT1 had altered distribution in Q175/Q7 HD striata of 6-month old mice but not 2-month old mice. These proteins are found on plasma membranes and pre- and postsynaptic membranes supporting hypotheses that functional changes at synapses contribute to cognitive and behavioral symptoms of HD. Lipidomic analysis of mouse fractions indicated that compared to those of wild-type, fractions 1 and 2 of 6 months Q175/Q7 HD had altered levels of two species of PIP2, a phospholipid involved in synaptic signaling, increased levels of cholesterol ester and decreased cardiolipin species. At 2 months, increased levels of species of acylcarnitine, phosphatidic acid and sphingomyelin were measured. EM analysis showed that the contents of fractions 1 and 2 of Q7/Q7 and Q175/Q7 HD striata had a mix of isolated synaptic vesicles, vesicle filled axon terminals singly or in clusters, and ER and endosome-like membranes. However, those of Q175/Q7 striata contained significantly fewer and larger clumps of particles compared to those of Q7/Q7. Human HD postmortem putamen showed differences from control putamen in subcellular distribution of two proteins (Calnexin and GLUT3). Our biochemical, lipidomic and EM analysis show that the presence of the HD mutation conferred age dependent disruption of localization of synaptic proteins and lipids important for synaptic function. Our data demonstrate concrete biochemical changes suggesting altered integrity of synaptic compartments in HD mice that may mirror changes in HD patients and presage cognitive and psychiatric changes that occur in premanifest HD.
Collapse
|
25
|
Eshraghi M, Karunadharma PP, Blin J, Shahani N, Ricci EP, Michel A, Urban NT, Galli N, Sharma M, Ramírez-Jarquín UN, Florescu K, Hernandez J, Subramaniam S. Mutant Huntingtin stalls ribosomes and represses protein synthesis in a cellular model of Huntington disease. Nat Commun 2021; 12:1461. [PMID: 33674575 PMCID: PMC7935949 DOI: 10.1038/s41467-021-21637-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
The polyglutamine expansion of huntingtin (mHTT) causes Huntington disease (HD) and neurodegeneration, but the mechanisms remain unclear. Here, we found that mHtt promotes ribosome stalling and suppresses protein synthesis in mouse HD striatal neuronal cells. Depletion of mHtt enhances protein synthesis and increases the speed of ribosomal translocation, while mHtt directly inhibits protein synthesis in vitro. Fmrp, a known regulator of ribosome stalling, is upregulated in HD, but its depletion has no discernible effect on protein synthesis or ribosome stalling in HD cells. We found interactions of ribosomal proteins and translating ribosomes with mHtt. High-resolution global ribosome footprint profiling (Ribo-Seq) and mRNA-Seq indicates a widespread shift in ribosome occupancy toward the 5' and 3' end and unique single-codon pauses on selected mRNA targets in HD cells, compared to controls. Thus, mHtt impedes ribosomal translocation during translation elongation, a mechanistic defect that can be exploited for HD therapeutics.
Collapse
Affiliation(s)
- Mehdi Eshraghi
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Pabalu P. Karunadharma
- grid.214007.00000000122199231The Scripps Research Institute, Genomic Core, Jupiter, FL USA
| | - Juliana Blin
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | - Neelam Shahani
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Emiliano P. Ricci
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | | | | | - Nicole Galli
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Manish Sharma
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Uri Nimrod Ramírez-Jarquín
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Katie Florescu
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Jennifer Hernandez
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Srinivasa Subramaniam
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| |
Collapse
|
26
|
Axenhus M, Winblad B, Tjernberg LO, Schedin-Weiss S. Huntingtin Levels are Elevated in Hippocampal Post-Mortem Samples of Alzheimer's Disease Brain. Curr Alzheimer Res 2021; 17:858-867. [PMID: 33272184 DOI: 10.2174/1567205017666201203125622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 10/01/2020] [Accepted: 10/19/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND We have recently identified Huntingtin (Htt), the pathogenic protein in Huntington's disease, as a mediator of Alzheimer's disease (AD) pathology in an amyloid precursor protein (APP) knock-in mouse model of AD. That finding prompted us to examine if Htt is accumulated in the brains of AD patients and in which cell type Htt is present in the AD brain. OBJECTIVE To investigate whether location and levels of Htt are affected in hippocampus and frontal cortex in AD. METHODS Brains from AD patients (n=11) and controls (n=11) were stained for Htt using immunohistochemistry and signal intensity of Htt was quantified and localized in subregions and neurons. Confocal microscopy was used to characterize neuronal Htt localisation and its relationship with tau tangles and astrocytes. RESULTS Htt levels were increased in neuronal cells in the granular layer of the dentate gyrus, in CA1 and CA3 in hippocampus and in layer III of the frontal cortex. Htt was found in the soma, perinuclear space, thin neurites and nucleus of pyramidal neurons. Htt was present in neurons containing tau tangles but did not colocalize with astrocytes. CONCLUSION Htt accumulates in pyramidal neuron-rich areas including hippocampal subregions associated with memory and frontal cortex layer III. The accumulation of Htt in AD shows distinct cellular and morphological patterns and is not present in astrocytes. Clearly, further research is warranted to elucidate the role of Htt as a mediator of AD pathology and the potential use of Htt as a target in future therapeutic strategies.
Collapse
Affiliation(s)
- Michael Axenhus
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Bengt Winblad
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Lars O Tjernberg
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Sophia Schedin-Weiss
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| |
Collapse
|
27
|
Chiki A, Ricci J, Hegde R, Abriata LA, Reif A, Boudeffa D, Lashuel HA. Site-Specific Phosphorylation of Huntingtin Exon 1 Recombinant Proteins Enabled by the Discovery of Novel Kinases. Chembiochem 2021; 22:217-231. [PMID: 32805086 PMCID: PMC8698011 DOI: 10.1002/cbic.202000508] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/17/2020] [Indexed: 12/20/2022]
Abstract
Post-translational modifications (PTMs) within the first 17 amino acids (Nt17) of exon 1 of the Huntingtin protein (Httex1) play important roles in modulating its cellular properties and functions in health and disease. In particular, phosphorylation of threonine and serine residues (T3, S13, and/or S16) has been shown to inhibit Htt aggregation in vitro and inclusion formation in cellular and animal models of Huntington's disease (HD). In this paper, we describe a new and simple methodology for producing milligram quantities of highly pure wild-type or mutant Httex1 proteins that are site-specifically phosphorylated at T3 or at both S13 and S16. This advance was enabled by 1) the discovery and validation of novel kinases that efficiently phosphorylate Httex1 at S13 and S16 (TBK1), at T3 (GCK) or T3 and S13 (TNIK and HGK), and 2) the development of an efficient methodology for producing recombinant native Httex1 proteins by using a SUMO-fusion expression and purification strategy.[26] As a proof of concept, we demonstrate how this method can be applied to produce Httex1 proteins that are both site-specifically phosphorylated and fluorescently or isotopically labeled. Together, these advances should increase access to these valuable tools and expand the range of methods and experimental approaches that can be used to elucidate the mechanisms by which phosphorylation influences Httex1 or HTT structure, aggregation, interactome, and function(s) in health and disease.
Collapse
Affiliation(s)
- Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Jonathan Ricci
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Ramanath Hegde
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Luciano A. Abriata
- Protein Production and Structure Core Facility and Laboratory for Biomolecular ModelingEcole Polytechnique Fédérale de Lausanne (EPFL) and Swiss Institute of Bioinformatics (SIB)1015LausanneSwitzerland
| | - Andreas Reif
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Driss Boudeffa
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Hilal A. Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| |
Collapse
|
28
|
Bozzi M, Sciandra F. Molecular Mechanisms Underlying Muscle Wasting in Huntington's Disease. Int J Mol Sci 2020; 21:ijms21218314. [PMID: 33167595 PMCID: PMC7664236 DOI: 10.3390/ijms21218314] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by pathogenic expansions of the triplet cytosine-adenosine-guanosine (CAG) within the Huntingtin gene. These expansions lead to a prolongation of the poly-glutamine stretch at the N-terminus of Huntingtin causing protein misfolding and aggregation. Huntingtin and its pathological variants are widely expressed, but the central nervous system is mainly affected, as proved by the wide spectrum of neurological symptoms, including behavioral anomalies, cognitive decline and motor disorders. Other hallmarks of HD are loss of body weight and muscle atrophy. This review highlights some key elements that likely provide a major contribution to muscle atrophy, namely, alteration of the transcriptional processes, mitochondrial dysfunction, which is strictly correlated to loss of energy homeostasis, inflammation, apoptosis and defects in the processes responsible for the protein quality control. The improvement of muscular symptoms has proven to slow the disease progression and extend the life span of animal models of HD, underlining the importance of a deep comprehension of the molecular mechanisms driving deterioration of muscular tissue.
Collapse
Affiliation(s)
- Manuela Bozzi
- Dipartimento Universitario di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore di Roma, Largo F. Vito 1, 00168 Roma, Italy
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”– SCITEC Sede di Roma, Largo F. Vito 1, 00168 Roma, Italy;
- Correspondence:
| | - Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”– SCITEC Sede di Roma, Largo F. Vito 1, 00168 Roma, Italy;
| |
Collapse
|
29
|
Overhoff M, De Bruyckere E, Kononenko NL. Mechanisms of neuronal survival safeguarded by endocytosis and autophagy. J Neurochem 2020; 157:263-296. [PMID: 32964462 DOI: 10.1111/jnc.15194] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/21/2020] [Accepted: 09/08/2020] [Indexed: 12/11/2022]
Abstract
Multiple aspects of neuronal physiology crucially depend on two cellular pathways, autophagy and endocytosis. During endocytosis, extracellular components either unbound or recognized by membrane-localized receptors (termed "cargo") become internalized into plasma membrane-derived vesicles. These can serve to either recycle the material back to the plasma membrane or send it for degradation to lysosomes. Autophagy also uses lysosomes as a terminal degradation point, although instead of degrading the plasma membrane-derived cargo, autophagy eliminates detrimental cytosolic material and intracellular organelles, which are transported to lysosomes by means of double-membrane vesicles, referred to as autophagosomes. Neurons, like all non-neuronal cells, capitalize on autophagy and endocytosis to communicate with the environment and maintain protein and organelle homeostasis. Additionally, the highly polarized, post-mitotic nature of neurons made them adopt these two pathways for cell-specific functions. These include the maintenance of the synaptic vesicle pool in the pre-synaptic terminal and the long-distance transport of signaling molecules. Originally discovered independently from each other, it is now clear that autophagy and endocytosis are closely interconnected and share several common participating molecules. Considering the crucial role of autophagy and endocytosis in cell type-specific functions in neurons, it is not surprising that defects in both pathways have been linked to the pathology of numerous neurodegenerative diseases. In this review, we highlight the recent knowledge of the role of endocytosis and autophagy in neurons with a special focus on synaptic physiology and discuss how impairments in genes coding for autophagy and endocytosis proteins can cause neurodegeneration.
Collapse
Affiliation(s)
- Melina Overhoff
- CECAD Cluster of Excellence, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Elodie De Bruyckere
- CECAD Cluster of Excellence, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Natalia L Kononenko
- CECAD Cluster of Excellence, Institute for Genetics, University of Cologne, Cologne, Germany
| |
Collapse
|
30
|
Neueder A, Orth M. Mitochondrial biology and the identification of biomarkers of Huntington's disease. Neurodegener Dis Manag 2020; 10:243-255. [PMID: 32746707 DOI: 10.2217/nmt-2019-0033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Apart from finding novel compounds for treating Huntington's disease (HD) an important challenge at present consists in finding reliable read-outs or biomarkers that reflect key biological processes involved in HD pathogenesis. The core elements of HD biology, for example, HTT RNA levels or protein species can serve as biomarker, as could measures from biological systems or pathways in which Huntingtin plays an important role. Here we review the evidence for the involvement of mitochondrial biology in HD. The most consistent findings pertain to mitochondrial quality control, for example, fission/fusion. However, a convincing mitochondrial signature with biomarker potential is yet to emerge. This requires more research including in peripheral sources of human material, such as blood, or skeletal muscle.
Collapse
Affiliation(s)
| | - Michael Orth
- Department of Neurology, Ulm University, Ulm, Germany.,SwissHuntington's Disease Centre, Neurozentrum Siloah, Worbstr. 312, 3073 Gümligenbei Bern, Switzerland
| |
Collapse
|
31
|
Wilton DK, Stevens B. The contribution of glial cells to Huntington's disease pathogenesis. Neurobiol Dis 2020; 143:104963. [PMID: 32593752 DOI: 10.1016/j.nbd.2020.104963] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/07/2020] [Accepted: 06/10/2020] [Indexed: 12/20/2022] Open
Abstract
Glial cells play critical roles in the normal development and function of neural circuits, but in many neurodegenerative diseases, they become dysregulated and may contribute to the development of brain pathology. In Huntington's disease (HD), glial cells both lose normal functions and gain neuropathic phenotypes. In addition, cell-autonomous dysfunction elicited by mutant huntingtin (mHTT) expression in specific glial cell types is sufficient to induce both pathology and Huntington's disease-related impairments in motor and cognitive performance, suggesting that these cells may drive the development of certain aspects of Huntington's disease pathogenesis. In support of this imaging studies in pre-symptomatic HD patients and work on mouse models have suggested that glial cell dysfunction occurs at a very early stage of the disease, prior to the onset of motor and cognitive deficits. Furthermore, selectively ablating mHTT from specific glial cells or correcting for HD-induced changes in their transcriptional profile rescues some HD-related phenotypes, demonstrating the potential of targeting these cells for therapeutic intervention. Here we review emerging research focused on understanding the involvement of different glial cell types in specific aspects of HD pathogenesis. This work is providing new insight into how HD impacts biological functions of glial cells in the healthy brain as well as how HD induced dysfunction in these cells might change the way they integrate into biological circuits.
Collapse
Affiliation(s)
- Daniel K Wilton
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Beth Stevens
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Stanley Center, Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
32
|
Taran AS, Shuvalova LD, Lagarkova MA, Alieva IB. Huntington's Disease-An Outlook on the Interplay of the HTT Protein, Microtubules and Actin Cytoskeletal Components. Cells 2020; 9:E1514. [PMID: 32580314 PMCID: PMC7348758 DOI: 10.3390/cells9061514] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
Huntington's disease is a severe and currently incurable neurodegenerative disease. An autosomal dominant mutation in the Huntingtin gene (HTT) causes an increase in the polyglutamine fragment length at the protein N-terminus. The consequence of the mutation is the death of neurons, mostly striatal neurons, leading to the occurrence of a complex of motor, cognitive and emotional-volitional personality sphere disorders in carriers. Despite intensive studies, the functions of both mutant and wild-type huntingtin remain poorly understood. Surprisingly, there is the selective effect of the mutant form of HTT even on nervous tissue, whereas the protein is expressed ubiquitously. Huntingtin plays a role in cell physiology and affects cell transport, endocytosis, protein degradation and other cellular and molecular processes. Our experimental data mining let us conclude that a significant part of the Huntingtin-involved cellular processes is mediated by microtubules and other cytoskeletal cell structures. The review attempts to look at unresolved issues in the study of the huntingtin and its mutant form, including their functions affecting microtubules and other components of the cell cytoskeleton.
Collapse
Affiliation(s)
- Aleksandra S. Taran
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 1–73, Leninsky Gory, 119992 Moscow, Russia; (A.S.T.); (L.D.S.)
| | - Lilia D. Shuvalova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 1–73, Leninsky Gory, 119992 Moscow, Russia; (A.S.T.); (L.D.S.)
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 1a Malaya Pirogovskaya St., 119435 Moscow, Russia
| | - Maria A. Lagarkova
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 1a Malaya Pirogovskaya St., 119435 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 1a Malaya Pirogovskaya St., 119435 Moscow, Russia
| | - Irina B. Alieva
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 1a Malaya Pirogovskaya St., 119435 Moscow, Russia
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 1–40, Leninsky Gory, 119992 Moscow, Russia
| |
Collapse
|
33
|
Yang H, Yang S, Jing L, Huang L, Chen L, Zhao X, Yang W, Pan Y, Yin P, Qin ZS, Tang B, Li S, Li XJ. Truncation of mutant huntingtin in knock-in mice demonstrates exon1 huntingtin is a key pathogenic form. Nat Commun 2020; 11:2582. [PMID: 32444599 PMCID: PMC7244548 DOI: 10.1038/s41467-020-16318-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 04/21/2020] [Indexed: 12/22/2022] Open
Abstract
Polyglutamine expansion in proteins can cause selective neurodegeneration, although the mechanisms are not fully understood. In Huntington’s disease (HD), proteolytic processing generates toxic N-terminal huntingtin (HTT) fragments that preferentially kill striatal neurons. Here, using CRISPR/Cas9 to truncate full-length mutant HTT in HD140Q knock-in (KI) mice, we show that exon 1 HTT is stably present in the brain, regardless of truncation sites in full-length HTT. This N-terminal HTT leads to similar HD-like phenotypes and age-dependent HTT accumulation in the striatum in different KI mice. We find that exon 1 HTT is constantly generated but its selective accumulation in the striatum is associated with the age-dependent expression of striatum-enriched HspBP1, a chaperone inhibitory protein. Our findings suggest that tissue-specific chaperone function contributes to the selective neuropathology in HD, and highlight the therapeutic potential in blocking generation of exon 1 HTT. The mechanisms by which mutant Huntington protein Htt leads to selective neurodegeneration are not fully understood. Here, using gene editing in HD140Q knock-in mice, the authors show that exon1 Htt is a critical pathological form of the protein.
Collapse
Affiliation(s)
- Huiming Yang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 510080, Guangzhou, China.,Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, 510632, Guangzhou, China.,Department of Neurology, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China.,Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Su Yang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, 510632, Guangzhou, China
| | - Liang Jing
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Emergency, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, China
| | - Luoxiu Huang
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Luxiao Chen
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, 30322, USA
| | - Xianxian Zhao
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, 510632, Guangzhou, China
| | - Weili Yang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, 510632, Guangzhou, China
| | - Yongcheng Pan
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Hunan, China
| | - Peng Yin
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, 510632, Guangzhou, China
| | - Zhaohui S Qin
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, 30322, USA
| | - Beisha Tang
- Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Hunan, China
| | - Shihua Li
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, 510632, Guangzhou, China.
| | - Xiao-Jiang Li
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, 510632, Guangzhou, China.
| |
Collapse
|
34
|
Bartl S, Oueslati A, Southwell AL, Siddu A, Parth M, David LS, Maxan A, Salhat N, Burkert M, Mairhofer A, Friedrich T, Pankevych H, Balazs K, Staffler G, Hayden MR, Cicchetti F, Smrzka OW. Inhibiting cellular uptake of mutant huntingtin using a monoclonal antibody: Implications for the treatment of Huntington's disease. Neurobiol Dis 2020; 141:104943. [PMID: 32407769 DOI: 10.1016/j.nbd.2020.104943] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/08/2020] [Accepted: 05/06/2020] [Indexed: 12/24/2022] Open
Abstract
Huntington's disease (HD) is caused by a highly polymorphic CAG trinucleotide expansion in the gene encoding for the huntingtin protein (HTT). The resulting mutant huntingtin protein (mutHTT) is ubiquitously expressed but also exhibits the ability to propagate from cell-to-cell to disseminate pathology; a property which may serve as a new therapeutic focus. Accordingly, we set out to develop a monoclonal antibody (mAB) targeting a particularly exposed region close to the aa586 caspase-6 cleavage site of the HTT protein. This monoclonal antibody, designated C6-17, effectively binds mutHTT and is able to deplete the protein from cell culture supernatants. Using cell-based assays, we demonstrate that extracellular secretion of mutHTT into cell culture media and its subsequent uptake in recipient HeLa cells can be almost entirely blocked by mAB C6-17. Immunohistochemical stainings of post-mortem HD brain tissue confirmed the specificity of mAB C6-17 to human mutHTT aggregates. These findings demonstrate that mAB C6-17 not only successfully engages with its target, mutHTT, but also inhibits cell uptake suggesting that this antibody could interfere with the pathological processes of mutHTT spreading in vivo.
Collapse
Affiliation(s)
| | - Abid Oueslati
- Université Laval/Centre de recherche du CHU, Québec, Canada
| | | | - Alberto Siddu
- Université Laval/Centre de recherche du CHU, Québec, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | - Oskar W Smrzka
- AFFiRiS AG, Vienna, Austria; Ablevia biotech GmbH, Vienna, Austria
| |
Collapse
|
35
|
Loss of huntingtin function slows synaptic vesicle endocytosis in striatal neurons from the httQ140/Q140 mouse model of Huntington's disease. Neurobiol Dis 2020; 134:104637. [DOI: 10.1016/j.nbd.2019.104637] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 08/23/2019] [Accepted: 10/09/2019] [Indexed: 12/13/2022] Open
|
36
|
Srinageshwar B, Petersen RB, Dunbar GL, Rossignol J. Prion-like mechanisms in neurodegenerative disease: Implications for Huntington's disease therapy. Stem Cells Transl Med 2020; 9:559-566. [PMID: 31997581 PMCID: PMC7180288 DOI: 10.1002/sctm.19-0248] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 01/14/2020] [Indexed: 12/18/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG repeat expansions in the huntingtin gene resulting in the synthesis of a misfolded form of the huntingtin protein (mHTT) which is toxic. The current treatments for HD are only palliative. Some of the potential therapies for HD include gene therapy (using antisense oligonucleotides and clustered regularly interspaced short palindromic repeats-Cas9 system) and stem-cell-based therapies. Various types of stem cell transplants, such as mesenchymal stem cells, neural stem cells, and reprogrammed stem cells, have the potential to either replace the lost neurons or support the existing neurons by releasing trophic factors. Most of the transplants are xenografts and allografts; however, recent reports on HD patients who received grafts suggest that the mHTT aggregates are transferred from the host neurons to the grafted cells as well as to the surrounding areas of the graft by a "prion-like" mechanism. This observation seems to be true for autotransplantation paradigms, as well. This article reviews the different types of stem cells that have been transplanted into HD patients and their therapeutic efficacy, focusing on the transfer of mHTT from the host cells to the graft. Autotransplants of reprogramed stem cells in HD patients are a promising therapeutic option. However, this needs further attention to ensure a better understanding of the transfer of mHTT aggregates following transplantation of the gene-corrected cells back into the patient.
Collapse
Affiliation(s)
- Bhairavi Srinageshwar
- College of Medicine, Central Michigan University, Mount Pleasant, Michigan.,Field Neurosciences Institute Laboratory for Restorative Neurology, Central Michigan University, Mount Pleasant, Michigan.,Program in Neuroscience, Central Michigan University, Mount Pleasant, Michigan
| | - Robert B Petersen
- College of Medicine, Central Michigan University, Mount Pleasant, Michigan.,Program in Neuroscience, Central Michigan University, Mount Pleasant, Michigan
| | - Gary L Dunbar
- Field Neurosciences Institute Laboratory for Restorative Neurology, Central Michigan University, Mount Pleasant, Michigan.,Program in Neuroscience, Central Michigan University, Mount Pleasant, Michigan.,Department of Psychology, Central Michigan University, Mount Pleasant, Michigan.,Field Neurosciences Institute, Saginaw, Michigan
| | - Julien Rossignol
- College of Medicine, Central Michigan University, Mount Pleasant, Michigan.,Field Neurosciences Institute Laboratory for Restorative Neurology, Central Michigan University, Mount Pleasant, Michigan.,Program in Neuroscience, Central Michigan University, Mount Pleasant, Michigan
| |
Collapse
|
37
|
Targeting N-Terminal Huntingtin with a Dual-sgRNA Strategy by CRISPR/Cas9. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1039623. [PMID: 31828084 PMCID: PMC6881766 DOI: 10.1155/2019/1039623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/30/2019] [Accepted: 09/05/2019] [Indexed: 01/10/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder, caused by a CAG/polyglutamine (polyQ) repeat expansion in the Huntingtin (HTT) gene. The polyQ tract is located in and transcribed from N-terminal HTT of exon 1. HTT is a large multifaceted protein, which participates in a range of cellular functions. Previous studies have shown that truncated HTT, which lacks N-terminus, retains specific functions that can produce neuroprotective benefits. It gives an insight that it is possible to repair HD by removing deleterious N-terminal HTT with CRISPR/Cas9, without compromising functions of remaining HTT peptides. To successfully generate functional truncated HTT proteins, an alternative downstream ATG start codon that is capable of initiating truncated HTT expression is required. In this study, we searched all possible in-frame ATGs before exon 7 and demonstrated that one of them can indeed initiate the downstream GFP expression in plasmids. We then tried to remove endogenous N-terminal HTT with an optimized dual-sgRNA strategy by CRISPR/Cas9; however, we cannot detect obvious traits of truncated HTT expression. Our results suggest that noncanonical ATGs of N-terminal HTT may not be effective in the genomic context, as in the construct context. Nevertheless, our study examined the therapeutic efficacy of downstream noncanonical ATGs for protein translation and also provided an optimized dual-sgRNA strategy for further genome manipulation of the HTT gene.
Collapse
|
38
|
Tellone E, Galtieri A, Ficarra S. Reviewing Biochemical Implications of Normal and Mutated Huntingtin in Huntington's Disease. Curr Med Chem 2019; 27:5137-5158. [PMID: 31223078 DOI: 10.2174/0929867326666190621101909] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/08/2019] [Accepted: 05/22/2019] [Indexed: 12/17/2022]
Abstract
Huntingtin (Htt) is a multi-function protein of the brain. Normal Htt shows a common alpha-helical structure but conformational changes in the form with beta strands are the principal cause of Huntington's disease. Huntington's disease is a genetic neurological disorder caused by a repeated expansion of the CAG trinucleotide, causing instability in the N-terminal of the gene coding for the Huntingtin protein. The mutation leads to the abnormal expansion of the production of the polyglutamine tract (polyQ) resulting in the form of an unstable Huntingtin protein commonly referred to as mutant Huntingtin. Mutant Huntingtin is the cause of the complex neurological metabolic alteration of Huntington's disease, resulting in both the loss of all the functions of normal Huntingtin and the genesis of abnormal interactions due to the presence of this mutation. One of the problems arising from the misfolded Huntingtin is the increase in oxidative stress, which is common in many neurological diseases such as Alzheimer's, Parkinson's, Amyotrophic Lateral Sclerosis and Creutzfeldt-Jakob disease. In the last few years, the use of antioxidants had a strong incentive to find valid therapies for defence against neurodegenerations. Although further studies are needed, the use of antioxidant mixtures to counteract neuronal damages seems promising.
Collapse
Affiliation(s)
- Ester Tellone
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Antonio Galtieri
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Silvana Ficarra
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy
| |
Collapse
|
39
|
Soares TR, Reis SD, Pinho BR, Duchen MR, Oliveira JMA. Targeting the proteostasis network in Huntington's disease. Ageing Res Rev 2019; 49:92-103. [PMID: 30502498 PMCID: PMC6320389 DOI: 10.1016/j.arr.2018.11.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 12/31/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion mutation in the huntingtin protein. Expansions above 40 polyglutamine repeats are invariably fatal, following a symptomatic period characterised by choreiform movements, behavioural abnormalities, and cognitive decline. While mutant huntingtin (mHtt) is widely expressed from early life, most patients with HD present in mid-adulthood, highlighting the role of ageing in disease pathogenesis. mHtt undergoes proteolytic cleavage, misfolding, accumulation, and aggregation into inclusion bodies. The emerging model of HD pathogenesis proposes that the chronic production of misfolded mHtt overwhelms the chaperone machinery, diverting other misfolded clients to the proteasome and the autophagy pathways, ultimately leading to a global collapse of the proteostasis network. Multiple converging hypotheses also implicate ageing and its impact in the dysfunction of organelles as additional contributing factors to the collapse of proteostasis in HD. In particular, mitochondrial function is required to sustain the activity of ATP-dependent chaperones and proteolytic machinery. Recent studies elucidating mitochondria-endoplasmic reticulum interactions and uncovering a dedicated proteostasis machinery in mitochondria, suggest that mitochondria play a more active role in the maintenance of cellular proteostasis than previously thought. The enhancement of cytosolic proteostasis pathways shows promise for HD treatment, protecting cells from the detrimental effects of mHtt accumulation. In this review, we consider how mHtt and its post translational modifications interfere with protein quality control pathways, and how the pharmacological and genetic modulation of components of the proteostasis network impact disease phenotypes in cellular and in vivo HD models.
Collapse
Affiliation(s)
- Tânia R Soares
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Sara D Reis
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Brígida R Pinho
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK
| | - Jorge M A Oliveira
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK.
| |
Collapse
|
40
|
Martin DDO, Schmidt ME, Nguyen YT, Lazic N, Hayden MR. Identification of a novel caspase cleavage site in huntingtin that regulates mutant huntingtin clearance. FASEB J 2018; 33:3190-3197. [PMID: 30423259 DOI: 10.1096/fj.201701510rrr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Huntington disease (HD) is a progressive neurodegenerative disease that initially affects the striatum and leads to changes in behavior and loss of motor coordination. It is caused by an expansion in the polyglutamine repeat at the N terminus of huntingtin (HTT) that leads to aggregation of mutant HTT. The loss of wild-type function, in combination with the toxic gain of function mutation, initiates various cell death pathways. Wild-type and mutant HTT are regulated by different posttranslational modifications that can positively or negatively regulate their function or toxicity. In particular, we have previously shown that caspase cleavage of mutant HTT at amino acid position aspartate 586 (D586) by caspase-6 is critical for the pathogenesis of the disease in an HD mouse model. Herein, we describe the identification of a new caspase cleavage site at position D572 that is mediated by caspase-1. Inhibition of caspase-1 also appeared to decrease proteolysis at D586, likely by blocking the downstream activation of caspase-6 through caspase-1. Inhibition of caspase cleavage at D572 significantly decreased mutant HTT aggregation and significantly increased the turnover of soluble mutant HTT. This suggests that caspase-1 may be a viable target to inhibit caspase cleavage of mutant HTT at both D572 and D586 to promote mutant HTT clearance.-Martin, D. D. O., Schmidt, M. E., Nguyen, Y. T., Lazic, N., Hayden, M. R. Identification of a novel caspase cleavage site in huntingtin that regulates mutant huntingtin clearance.
Collapse
Affiliation(s)
- Dale D O Martin
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Mandi E Schmidt
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yen T Nguyen
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Nikola Lazic
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael R Hayden
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
41
|
Rosas-Arellano A, Estrada-Mondragón A, Piña R, Mantellero CA, Castro MA. The Tiny Drosophila Melanogaster for the Biggest Answers in Huntington's Disease. Int J Mol Sci 2018; 19:E2398. [PMID: 30110961 PMCID: PMC6121572 DOI: 10.3390/ijms19082398] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 12/18/2022] Open
Abstract
The average life expectancy for humans has increased over the last years. However, the quality of the later stages of life is low and is considered a public health issue of global importance. Late adulthood and the transition into the later stage of life occasionally leads to neurodegenerative diseases that selectively affect different types of neurons and brain regions, producing motor dysfunctions, cognitive impairment, and psychiatric disorders that are progressive, irreversible, without remission periods, and incurable. Huntington's disease (HD) is a common neurodegenerative disorder. In the 25 years since the mutation of the huntingtin (HTT) gene was identified as the molecule responsible for this neural disorder, a variety of animal models, including the fruit fly, have been used to study the disease. Here, we review recent research that used Drosophila as an experimental tool for improving knowledge about the molecular and cellular mechanisms underpinning HD.
Collapse
Affiliation(s)
- Abraham Rosas-Arellano
- Unidad de Imagenología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico.
| | - Argel Estrada-Mondragón
- Department of Clinical and Experimental Medicine, Linköping University, 581 83 Linköping, Sweden.
| | - Ricardo Piña
- Laboratorio de Neurociencias, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9160000, Chile.
- Departamento de Ciencias Químicas y Biológicas, Universidad Bernardo O'Higgins, Santiago 8370993, Chile.
| | - Carola A Mantellero
- Facultad de Ciencias de la Salud, Universidad de Las Américas, Santiago 7500972, Chile.
| | - Maite A Castro
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia 5090000, Chile.
- Center for Interdisciplinary Studies on the Nervous System (CISNe), Universidad Austral de Chile, Valdivia 5090000, Chile.
| |
Collapse
|
42
|
|
43
|
Pandey M, Rajamma U. Huntington's disease: the coming of age. J Genet 2018; 97:649-664. [PMID: 30027901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Huntington's disease (HD) is caused due to an abnormal expansion of polyglutamine repeats in the first exon of huntingtin gene. The mutation in huntingtin causes abnormalities in the functioning of protein, leading to deleterious effects ultimately to the demise of specific neuronal cells.The disease is inherited in an autosomal dominant manner and leads to a plethora of neuropsychiatric behaviour and neuronal cell death mainly in striatal and cortical regions of the brain, eventually leading to death of the individual. The discovery of the mutant gene led to a surge in molecular diagnostics of the disease and in making different transgenic models in different organisms to understand the function of wild-type and mutant proteins. Despite difficult challenges, there has been a significant increase in understanding the functioning of the protein in normal and other gain-of-function interactions in mutant form. However, there have been no significant improvements in treatments of the patients suffering from this ailment and most of the treatment is still symptomatic. HD warrants more attention towards better understanding and treatment as more advancement in molecular diagnostics and therapeutic interventions are available. Several different transgenic models are available in different organisms, ranging from fruit flies to primate monkeys, for studies on understanding the pathogenicity of the mutant gene. It is the right time to assess the advancement in the field and try new strategies for neuroprotection using key pathways as target. The present review highlights the key ingredients of pathology in the HD and discusses important studies for drug trials and future goals for therapeutic interventions.
Collapse
Affiliation(s)
- Mritunjay Pandey
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | | |
Collapse
|
44
|
Reif A, Chiki A, Ricci J, Lashuel HA. Generation of Native, Untagged Huntingtin Exon1 Monomer and Fibrils Using a SUMO Fusion Strategy. J Vis Exp 2018. [PMID: 30010666 PMCID: PMC6102005 DOI: 10.3791/57506] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Huntington's Disease (HD) is an inherited fatal neurodegenerative disease caused by a CAG expansion (≥36) in the first exon of the HD gene, resulting in the expression of the Huntingtin protein (Htt) or N-terminal fragments thereof with an expanded polyglutamine (polyQ) stretch. The exon1 of the Huntingtin protein (Httex1) is the smallest Htt fragment that recapitulates many of the features of HD in cellular and animal models and is one of the most widely studied fragments of Htt. The small size of Httex1 makes it experimentally more amenable to biophysical characterization using standard and high-resolution techniques in comparison to longer fragments or full-length Htt. However, the high aggregation propensity of mutant Httex1 (mHttex1) with increased polyQ content (≥42) has made it difficult to develop efficient expression and purification systems to produce these proteins in sufficient quantities and make them accessible to scientists from different disciplines without the use of fusion proteins or other strategies that alter the native sequence of the protein. We present here a robust and optimized method for the production of milligram quantities of native, tag-free Httex1 based on the transient fusion of small ubiquitin related modifier (SUMO). The simplicity and efficiency of the strategy will eliminate the need to use non-native sequences of Httex1, thus making this protein more accessible to researchers and improving the reproducibility of experiments across different laboratories. We believe that these advances will also facilitate future studies aimed at elucidating the structure-function relationship of Htt as well as developing novel diagnostic tools and therapies to treat or slow the progression of HD.
Collapse
Affiliation(s)
- Andreas Reif
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL)
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL)
| | - Jonathan Ricci
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL)
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL);
| |
Collapse
|
45
|
A human huntingtin SNP alters post-translational modification and pathogenic proteolysis of the protein causing Huntington disease. Sci Rep 2018; 8:8096. [PMID: 29802276 PMCID: PMC5970160 DOI: 10.1038/s41598-018-25903-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 04/30/2018] [Indexed: 11/23/2022] Open
Abstract
Post-translational modifications (PTMs) are key modulators of protein function. Huntington disease (HD) is a dominantly inherited neurodegenerative disorder caused by an expanded CAG trinucleotide repeat in the huntingtin (HTT) gene. A spectrum of PTMs have been shown to modify the normal functions of HTT, including proteolysis, phosphorylation and lipidation, but the full contribution of these PTMs to the molecular pathogenesis of HD remains unclear. In this study, we examine all commonly occurring missense mutations in HTT to identify potential human modifiers of HTT PTMs relevant to HD biology. We reveal a SNP that modifies post-translational myristoylation of HTT, resulting in downstream alterations to toxic HTT proteolysis in human cells. This is the first SNP shown to functionally modify a PTM in HD and the first validated genetic modifier of post-translational myristoylation. This SNP is a high-priority candidate modifier of HD phenotypes and may illuminate HD biology in human studies.
Collapse
|
46
|
McClory H, Wang X, Sapp E, Gatune LW, Iuliano M, Wu CY, Nathwani G, Kegel-Gleason KB, DiFiglia M, Li X. The COOH-terminal domain of huntingtin interacts with RhoGEF kalirin and modulates cell survival. Sci Rep 2018; 8:8000. [PMID: 29789657 PMCID: PMC5964228 DOI: 10.1038/s41598-018-26255-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 05/01/2018] [Indexed: 12/14/2022] Open
Abstract
Human huntingtin (Htt) contains 3144 amino acids and has an expanded polyglutamine region near the NH2-terminus in patients with Huntington's disease. While numerous binding partners have been identified to NH2-terminal Htt, fewer proteins are known to interact with C-terminal domains of Htt. Here we report that kalirin, a Rac1 activator, is a binding partner to C-terminal Htt. Kalirin and Htt co-precipitated from mouse brain endosomes and co-localized at puncta in NRK and immortalized striatal cells and primary cortical neurons. We mapped the interaction domains to kalirin674-1272 and Htt2568-3144 and determined that the interaction between kalirin and Htt was independent of HAP1, a known interactor for Htt and kalirin. Kalirin precipitated with mutant Htt was more abundant than with wild-type Htt and had a reduced capacity to activate Rac1 when mutant Htt was present. Expression of Htt2568-3144 caused cytotoxicity, partially rescued by co-expressing kalirin674-1272 but not other regions of kalirin. Our study suggests that the interaction of kalirin with the C-terminal region of Htt influences the function of kalirin and modulates the cytotoxicity induced by C-terminal Htt.
Collapse
Affiliation(s)
- Hollis McClory
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Xiaolong Wang
- School of Pharmacy, Shanghai Jiao Tong University, Minhang District, Shanghai, China
| | - Ellen Sapp
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Leah W Gatune
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Maria Iuliano
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Chiu-Yi Wu
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Gina Nathwani
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Kimberly B Kegel-Gleason
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Marian DiFiglia
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Xueyi Li
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA.
- School of Pharmacy, Shanghai Jiao Tong University, Minhang District, Shanghai, China.
| |
Collapse
|
47
|
Farah R, Haraty H, Salame Z, Fares Y, Ojcius DM, Said Sadier N. Salivary biomarkers for the diagnosis and monitoring of neurological diseases. Biomed J 2018; 41:63-87. [PMID: 29866603 PMCID: PMC6138769 DOI: 10.1016/j.bj.2018.03.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 03/13/2018] [Accepted: 03/29/2018] [Indexed: 12/17/2022] Open
Abstract
Current research efforts on neurological diseases are focused on identifying novel disease biomarkers to aid in diagnosis, provide accurate prognostic information and monitor disease progression. With advances in detection and quantification methods in genomics, proteomics and metabolomics, saliva has emerged as a good source of samples for detection of disease biomarkers. Obtaining a sample of saliva offers multiple advantages over the currently tested biological fluids as it is a non-invasive, painless and simple procedure that does not require expert training or harbour undesirable side effects for the patients. Here, we review the existing literature on salivary biomarkers and examine their validity in diagnosing and monitoring neurodegenerative and neuropsychiatric disorders such as autism and Alzheimer's, Parkinson's and Huntington's disease. Based on the available research, amyloid beta peptide, tau protein, lactoferrin, alpha-synuclein, DJ-1 protein, chromogranin A, huntingtin protein, DNA methylation disruptions, and micro-RNA profiles provide display a reliable degree of consistency and validity as disease biomarkers.
Collapse
Affiliation(s)
- Raymond Farah
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Hayat Haraty
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Ziad Salame
- Research Department, Faculty of Dental Medicine, Lebanese University, Beirut, Lebanon
| | - Youssef Fares
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - David M Ojcius
- Department of Biomedical Sciences, University of the Pacific, Arthur Dugoni School of Dentistry, San Francisco, CA, USA.
| | - Najwane Said Sadier
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon.
| |
Collapse
|
48
|
Youssov K, Bachoud-Lévi AC. Malattia di Huntington: aspetti diagnostici attuali e applicazioni pratiche. Neurologia 2018. [DOI: 10.1016/s1634-7072(18)89403-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
49
|
Caterino M, Squillaro T, Montesarchio D, Giordano A, Giancola C, Melone MAB. Huntingtin protein: A new option for fixing the Huntington's disease countdown clock. Neuropharmacology 2018. [PMID: 29526547 DOI: 10.1016/j.neuropharm.2018.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Huntington's disease is a dreadful, incurable disorder. It springs from the autosomal dominant mutation in the first exon of the HTT gene, which encodes for the huntingtin protein (HTT) and results in progressive neurodegeneration. Thus far, all the attempted approaches to tackle the mutant HTT-induced toxicity causing this disease have failed. The mutant protein comes with the aberrantly expanded poly-glutamine tract. It is primarily to blame for the build-up of β-amyloid-like HTT aggregates, deleterious once broadened beyond the critical ∼35-37 repeats threshold. Recent experimental findings have provided valuable information on the molecular basis underlying this HTT-driven neurodegeneration. These findings indicate that the poly-glutamine siding regions and many post-translation modifications either abet or counter the poly-glutamine tract. This review provides an overall, up-to-date insight into HTT biophysics and structural biology, particularly discussing novel pharmacological options to specifically target the mutated protein and thus inhibit its functions and toxicity.
Collapse
Affiliation(s)
- Marco Caterino
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy
| | - Tiziana Squillaro
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Daniela Montesarchio
- InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, 80126, Napoli, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA; Department of Medicine, Surgery and Neuroscience University of Siena, Siena, Italy
| | - Concetta Giancola
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy.
| | - Mariarosa A B Melone
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.
| |
Collapse
|
50
|
Ehrnhoefer DE, Martin DDO, Schmidt ME, Qiu X, Ladha S, Caron NS, Skotte NH, Nguyen YTN, Vaid K, Southwell AL, Engemann S, Franciosi S, Hayden MR. Preventing mutant huntingtin proteolysis and intermittent fasting promote autophagy in models of Huntington disease. Acta Neuropathol Commun 2018; 6:16. [PMID: 29510748 PMCID: PMC5839066 DOI: 10.1186/s40478-018-0518-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/12/2018] [Indexed: 12/20/2022] Open
Abstract
Huntington disease (HD) is caused by the expression of mutant huntingtin (mHTT) bearing a polyglutamine expansion. In HD, mHTT accumulation is accompanied by a dysfunction in basal autophagy, which manifests as specific defects in cargo loading during selective autophagy. Here we show that the expression of mHTT resistant to proteolysis at the caspase cleavage site D586 (C6R mHTT) increases autophagy, which may be due to its increased binding to the autophagy adapter p62. This is accompanied by faster degradation of C6R mHTT in vitro and a lack of mHTT accumulation the C6R mouse model with age. These findings may explain the previously observed neuroprotective properties of C6R mHTT. As the C6R mutation cannot be easily translated into a therapeutic approach, we show that a scheduled feeding paradigm is sufficient to lower mHTT levels in YAC128 mice expressing cleavable mHTT. This is consistent with a previous model, where the presence of cleavable mHTT impairs basal autophagy, while fasting-induced autophagy remains functional. In HD, mHTT clearance and autophagy may become increasingly impaired as a function of age and disease stage, because of gradually increased activity of mHTT-processing enzymes. Our findings imply that mHTT clearance could be enhanced by a regulated dietary schedule that promotes autophagy.
Collapse
|